In the prior art, as illustrated in FIG. 1, a drive system 10 includes a pair of elongated driveshafts 12, 14 that are arranged to be substantially parallel. Each of driveshafts 12, 14 are rotatably coupled to a frame member 16 via a respective bearing 18, 20. Coupled to the ends of driveshafts 12, 14, is a respective sprocket 22, 24, which are drivably coupled by a chain (not shown) in a manner as is well known in the art. In this prior art arrangement, the teeth of sprockets 22, 24 are cantilevered outward on respective driveshafts 12, 14 with respect to bearings 18, 20. Accordingly, for example, under the high loads that drive the row units of a corn head via sprockets 22, 24, this prior art arrangement results in forces in directions F1 and F2, and in turn results in the flexing of driveshafts 12, 14, as illustrated by curved lines C1 and C2. As a result of the flexing of driveshafts 12, 14, the chains that drive, or are driven by, the driveshafts 12, 14 are bent and wear rapidly.
What is needed, therefore, is an improved combine row unit drive system that is more rigid and reduces wear on the sprockets and chains.